The present invention relates to an electromagnetic release device for a single-lens reflex camera in which current is applied to an electromagnet to lift a mirror.
In general, in a conventional electromagnetic release device of this type, in response to a shutter release signal, current is applied to an electromagnet to release an armature, to turn an armature lever, and thereby unlock a mirror driving lever. As a result, the mirror driving lever is turned by an elastic force to lift the mirror. When the mirror has been lifted, the shutter top curtain is run to start exposure. The armature is reset (attracted by the electromagnet) again when a mirror charge member is operated in the next winding operation or when the mirror is restored after the exposure.
In the conventional device, the armature is maintained separated from the core of the electromagnet until the next winding operation, or in the case where the time of exposure is long, the armature is apart from the core for that time. Accordingly, in this operation, dust such as iron powder is liable to adhere to the attraction surfaces of the electromagnet and the armature. If foreign matter such as dust sticks to the attraction surfaces, then the electromagnet cannot satisfactorily attract the armature, which is one cause of shutter failure.